.NET 實作DES加密解密處理

.NET 實作DES加密解密處理

using System; 
using System.Text; 
using System.Security.Cryptography;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string a1 = EncryptDES("123123123123");
            Console.WriteLine(a1);
            string a2 = DecryptDES(a1);
            Console.WriteLine(a2); 
            Console.Read();  
        }
        //預設密鑰向量
        private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
        //預設加密密碼
        private static string DefEncryptKey = "consmkey";
        /// <summary>
        /// DES加密字元串
        /// </summary>
        /// <param name="encryptString">待加密的字元串</param>
        /// <returns>加密成功傳回加密後的字元串，失敗傳回源串</returns>
        public static string EncryptDES(string encryptString)
        {
            return EncryptDES(encryptString, DefEncryptKey);
        }

        /// <summary>
        /// DES解密字元串
        /// </summary>
        /// <param name="decryptString">待解密的字元串</param>
        /// <returns>解密成功傳回解密後的字元串，失敗返源串</returns>
        public static string DecryptDES(string decryptString)
        {
            return DecryptDES(decryptString, DefEncryptKey);
        }

        /// <summary>
        /// DES加密字元串
        /// </summary>
        /// <param name="encryptString">待加密的字元串</param>
        /// <param name="encryptKey">加密密鑰,要求為8位</param>
        /// <returns>加密成功傳回加密後的字元串，失敗傳回源串</returns>
        public static string EncryptDES(string encryptString, string encryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());
            }
            catch
            {
                return encryptString;
            }
        }

        /// <summary>
        /// DES解密字元串
        /// </summary>
        /// <param name="decryptString">待解密的字元串</param>
        /// <param name="decryptKey">解密密鑰,要求為8位,和加密密鑰相同</param>
        /// <returns>解密成功傳回解密後的字元串，失敗返源串</returns>
        public static string DecryptDES(string decryptString, string decryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }
    }  
}